Electrostatic paint overspray naturally builds up on the paint carrier and conveyor structures such as an overhead conveyor. Such buildup requires frequent cleaning and high part reject rates due to solidified particles dropping down upon newly painted part surfaces.
Various prior art patents have attempted to deal with the problem of paint overspray and other problems in systems wherein paint is sprayed on parts supported on a spindle suspended from a moving conveyor.
For example, the Bagby et al U.S. Pat. No. 4,289,090 discloses an electrostatically isolated carrier for painting apparatus. The apparatus includes a rail member having a pair of electrically insulated sleeve members for carrying workpieces to be painted. The work pieces are normally carried by electrically non-conductive hooks which are coated with a plastic material which is nylon. The insulated sleeves may comprise polypropylene or nylon.
The Pfender U.S. Pat. No. 4,290,383 discloses an electrostatic paint spraying arrangement wherein excess paint or coating material is deposited on a backup shield which is porous to absorb excess paint or coating material, thereby minimizing paint overspray.
The Richards et al U.S. Pat. No. 4,325,319 discloses an air flow system for the charging conductor in an electrostatic painting system whereby the air flow system is utilized to prevent paint particles from depositing on the conductor and to avoid deposition of paint on charged conductors. A rack has a flat disc shape which is hung from a conveyor from which workpieces to be painted are suspended.
The Hafele et al U.S. Pat. No. 4,120,261 discloses an electrostatic coating system within a workpiece charging system. A rack having a flat disc shape from which workpieces are suspended is, in turn, suspended from a conveyor.
The Bagby et al U.S. Pat. No. 4,158,344 discloses an electrostatic coating system having means for directing an electrostatic charge to a workpiece carried on a supporting hook. The supporting hook, in turn, is hung from a rack which has a flat disc-shaped configuration and is, in turn, hung from a conveyor.
Despite the teachings of the prior art there is a need for a device which is not only capable of catching solidified paint particles which fall off the conveyor during use, but also is capable of electrically insulating or shielding electrostatically charged paint particles from the conveyor.